Metrology Error Reduction via Target Segmentation and Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current overlay metrology systems are prone to errors due to process variations, lithography processes, and metrology processes, leading to increased throughput measurement time and the need for additional calibration.
Innovation Solution
A system and method that utilize multiple metrology targets with different or identical target designs, and a controller to receive and analyze measurements, determining errors and correctables to reduce noise in metrology measurements, including the use of advanced imaging metrology targets and scatterometry overlay targets with multiple pitches and layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple metrology targets with different target designs are used, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The metrology sample is divided into multiple distinct metrology targets, each with specific target designs optimized for measuring different error sources. This segmentation allows each target to specialize in capturing particular measurement aspects, improving overall accuracy while maintaining manageable complexity through modular design
Solution Approach 2:
Different regions of the metrology sample contain different target designs tailored to specific measurement needs. Each target design is locally optimized for its intended measurement purpose, such as measuring process variations versus lithography errors, thereby improving measurement precision without requiring uniform complexity across the entire system
2Reliability
If additional calibration is performed to reduce error sources, then measurement reliability is improved, but measurement time increases
Solution Approach 1:
Multiple metrology targets are measured simultaneously or in parallel during the measurement process, rather than sequentially performing separate calibration procedures. This preliminary action of capturing multiple measurement types in one operation reduces total measurement time while maintaining reliability through comprehensive error source characterization
Solution Approach 2:
The system uses the measurements from multiple target designs to generate feedback information about different error sources, which is then used to adjust and improve measurement accuracy. This feedback mechanism enables the system to achieve high reliability without requiring multiple separate calibration cycles, thereby reducing measurement time
Data Source
AI summary
A metrology system includes a controller communicatively coupled to one or more metrology tools, the controller including one or more processors configured to execute program instructions causing the one or more processors to receive one or more metrology measurements of one or more metrology targets of a metrology sample, a metrology target of the one or more metrology targets including one or more target designs with one or more cells, the one or more target designs being generated on one or more layers of the metrology sample; determine one or more errors based on the one or more metrology measurements; and determine one or more correctables to adjust one or more sources of error corresponding to the one or more errors, the one or more correctables being configured to reduce an amount of noise in the one or more metrology measurements generated by the one or more sources of errors.